Studies show that environmental, cultural, socioeconomic, and geographical factors are the controllers of the number of plant species used by human communities.
I am sure you will get a volume of information in this account from papers of Dr. R.K. Maikhuri from G.B. Pant Institute Srinagar, Garhwal. All the best...
Please let me know if the following reference/site is helpful to you:
Plants Are Medicine - National Geographic Society
https://voices.nationalgeographic.org/2016/11/04/all-plants-are-medicine/Nov 4, 2016 ... All Plants Are Medicine; We Just Need To (re)Learn How ... The collection was assembled to document these plants and traditional knowledge ...
There are various studies which suggest geographical factors impact on collection an d utilization of medicinal plants with respect to availability/ accessibility to alkaloid content and cultivation